Hopper unit for concrete slab laying machines



y 3, 1963 R. M. GUNTERT ETAL 3,

HOPPER UNIT FOR CONCRETE SLAB LAYING MACHINES Filed NOV. 21, 1960 2 s s 1 25 35 IN VENTOR Ronald .M'. 6Lmerl F zzwywdza- ATTORNEYS y 1963 R. M. GUNTERT ETAL 3,093,415

HOPPER UNIT FOR CONCRETE SLAB LAYING MACHINES Filed Nov. 21. 1960 2 he s-Sheet 2 United States Patent M 3,098,415 HOPPER UNIT FOR CQNCRETE SLAB LAYHN'G MACHINES Ronald M. Guntert, Stockton, Califl, assignor to Guntert & Zimmerman Const. Div., Ina, Stockton, Calm, a corporation of California Filed Nov. 21, 1960, Ser. No. 70,554- 5 Claims. (Cl. 94-46) The present invention relates to improvements, in a slab laying machine, which enhance the control and quality of the material, such as concrete mix, placed on a sub-grade. While especially designed for use in connection with a concrete slab laying machine for highway construction and is hereinafter so described, the invention is not restricted to such an adaptation and can be embodied in machines for placing material, whether concrete or other mix, on the sub-grade of different structures such as airport landing strips, canals, dams, etc.

In the slab laying machine, the mix is deposited in controlled quantity and at selective points in a frame-supported, forwardly mounted, transversely extending hopper by means of a mix receiving, feeding and blending receptacle-such as a bucketmovable transversely back and forth above but closely adjacent the hopper; there being a pan or screed on the frame above the prepared subgrade immediately rearwardly of the hopper, and said hopper-in which a quantity of the mix always remainscontinuously and directly distributing such mix in unbroken fiow onto such sub-grade so that the pan as it works in following relation spreads the mix to proper thickness as well as surfacing the resultant slab.

As the machine advanced there was heretofore a tendency for the concrete mix, as deposited on the sub-grade, to recurringly surge rearwardly toward the pan, and due-among factorsto the fluctuation of the amount of mix in the hopper and attendant increase or decrease in the head pressure of said mix. Such rearward surging was transmitted in the mix beneath the pan and to the formed slab back of said pan; the result being undesirable waves in such slab.

It is, therefore, the major object of this invention to provide, in a concrete slab laying machine of the type described, a novel hopper unit which is constructed in a manner and operative in association with said feeding receptacle to prevent such surge of the mix in the direction of and beneath the pan, whereby to preclude the formation of the undesirable waves in the concrete slab as laid by the machine. Such hopper unit is a modification of the corresponding part of the machine illustrated in co-pending United States patent application Serial No. 15,871, filed March 18, 1960.

Another important object of this invention is to provide a hopper unit, as in the preceding paragraph, which includes means definingimmediately ahead of and conjunctively related to the panan open bottom, upwardly extending, surge damping chamber in which the concrete mix can rise and fall to compensate for the aforesaid increase and decrease in the head pressure of the mix before it enters beneath the pan. In this way the head pressure on the mix, beneath said pan, is equalized or maintained substantially constant, and the slab is thus produced with a uniform surface. Such surge chamber also serves to compensate for or absorb rearward surging in the mix which under certain circumstances may also be caused by a vibrator assembly which is associated with the hopper unit for the purpose of consolidating the mix as deposited on the sub-grade but before entry under the pan.

An additional object of the invention is to provide a hopper unit, as above, which is adjustably gated at the 3,098,415 Patented July 23, 1963 front, bafiled at points in its transverse extent, and embraces a novel vibrator assembly; all in the manner and for the purposes hereinafter described.

A further object of the invention is to provide a practical, reliable, and durable hopper unit for concrete slab laying machines, and a hopper unit which is exceedingly effective for the accomplishment of the purposes for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

FIG. 1 is a sectional elevation, taken in a longitudinal vertical plane, of the improved hopper unit as mounted in connection with a slab laying machine; the latter being shown only in part, and mainly in elevational outline.

FIG. 2 is a foreshortened, transverse sectional elevation, substantially on line 2-2 of FIG. 1.

FIG. 3 is a foreshortened, fragmentary plan View, partly in section, substantially on line 3-3 of FIG. 2.

Referring now more particularly to the drawings, and to the characters of reference marked thereon, the novel hopper unit is mounted in connection with a concrete slab laying machine, indicated generally and in part at 1; such machine including a rigid main frame 2 suitably supported above, and for travel along, the sub-grade 3. The main frame 2 is provided, at the bottom, with a longitudinally extending pan or screed 4 spaced above the sub-grade '3. At its front end the pan 4, which is of a width at least equal to that of the slab, includes a for wardly and upwardly inclined lip 5.

A roller carriage 6 is mounted atop the from portion of the main frame 2 for back and forth powered travel transversely thereof; such roller carriage being fitted with a forwardly projecting arm structure 7 which includes a downwardly offset portion 7a intermediate its ends, and a lower front portion 7b extending some distance ahead of said main frame '2. The front portion 7b of the arm structure 7 supports a concrete mix receiving, {feeding and blending receptacle or bucket 8 having a mix flow control gate 9 at the bottom thereof. The bucket 8, by means of the carriage 6, is adapted [to be shuttled back and forth transversely of the machine; said bucket 8 being supplied with concrete mix from any suitable type of apparatus, such as a mixer, disposed alongside the sub-grade 3.

By reason of the mounting of the bucket 8 in connection with the downwardly offset front portion 712 of the arm structure 7, the top or receiving height of such bucket is relatively low which permits of ready loading of such bucket without undue elevation of the mix. the bucket 8 mounted as described, its discharge or feeding point is relatively low so as to minimize gravitational impact of the mix as discharged from said bucket 8 into a transversely extending, frame-supported mix accumulat ing and distributing hopper indicated generally at 10. The hopper 10 is forwardly mounted on the main frame 2 ahead of the pan 4 above the sub-grade 3 and below the bucket 8. v

The bucket 8, as moved back and forth above the hopper ltl, serves the purpose not only of feeding mix to I said hopper with a minimum of gravitational impact, but also makes possible the feeding of the mix to selected points in the hopper to blend as well as equalize the load therein.

The hopper 10, which is supported in part by longitudinal side beams 11 which project forwardly from the main frame 2, comprises a rear wall 12 disposed at a forward and downward incline, and merging at its lower edge with the upper edge of the lip *5; the latter thus forming a part of the rear wall of the hopper. Vertical end walls lfi having predetermined clearance above the sub- Also, with grade-project forwardly from the rear wall 12, and a front wall 14 extends between the forward portions of said end walls 13. The front wall 14 is pivoted, as at 15, for forward or rearward adjustment, being maintained in any selected position of adjustment by suitable means, such as a quadrant arrangement as shown. The front wall 14 includes a depending vertically adjustable front gate 14:: whereby to permit, and yet control, flow of the mix to some extent onto the sub-grade ahead of the machine. This forward flow of the mix permits placing thereof up to an adjoining slab, supplements the voluumetric capacity of the hopper, and aids-together with the hereinafter described surge chamber-in minimizing the undesirable rearward surge of the mix beneath the pan; the gate 140, being adjustable, allowing setting for passage over obstructions, or over pre-placed, or concurrently placed, slab reinforcement.

The hopper 10, which is of a transverse width approximating that of the pan 4, includesat spaced points intermediate the end walls 13a plurality of vertically disposed, intermediate walls 16 which extend from the rear wall 12 to adjacent the front wall 14; the intermediate walls 16 being fitted at their upper edge with longitudinal bars 17. The intermediate walls 16 not only strengthen the hopper but prevent undue side flow of the mix, as for example-when the machine is working on a transverse slope.

Between each end wall 13 and the adjacent intermediate wall 16, and between adjacent intermediate walls 16, the hopper unit includes a forwardly facing baffie plate 18, each such baffie plate being fitted, at the upper edge, with a rod 19 carrying outwardly projecting trunnions 20 at the ends. Such t-runnions 20 are engaged in corresponding notches of upstanding brackets 21, each of which is formed with a vertical row of such notches in order that the baffle plates 18 may be adjusted up or down as desired. Certain of such upstanding, notched brackets are mounted in connection with the end walls 13, while the remainder of said brackets are fixed on the longitudinal bars 17 at the upper edges of the intermediate walls 16.

Adjacent but short of their lower edges, the bafiie plates 18 abut, at the rear, against stops 22; certain of such stops being on the end walls 13, while the remainder are on the intermediate walls 16-all as shown.

By mounting the transverse baflle plates 18 as above described, they can be adjusted up or down, and can also swing forwardly fromthe stops 22.

In any position of vertical adjustment of the baffle plates 18, their lower edges occupy a position in a horizontal plane above that of the pan 4, while the upper edges of said bafiie plates are always above the maximum height of the concrete mix in the mix-receiving portion or area of the hopper 10 between said baffle plates and the front wall, and into which portion of the hopper the concrete mix is delivered, in blending relation and with a minimum of gravitational impact, from the bucket 8.

A horizontal, transversely extending, tubular vibrator 23, preferably of eccentrically adjustable type, is mounted in a position directly ahead of the lower portion of the hp such vibrator here being shown as belt, driven, as at 24.

Longitudinal vibrators, such as electrically actuated stinger type, are mounted in connection with hopper and occupy a position beneath the mix-receiving portion or area thereof; one of such vibrators being indicated at 25. Each such longitudinal vibnator 25 is supported by a spring mount 26 adjustably secured to a horizontal, transversely extending cross shaft 27 carried on upwardly and rearwardly inclined arms, one of which is indicated at 28. Each such arm is pivoted, as at 29, to the back side of the front wall 14 adjacent its lower edge. The cross shaft 27 is vertically adjustably suspended by cable means 30 which extend upwardly to a Windlass shaft 31. As so mounted, the vibrators 25 are adjustable relative to the sub-grade 3 as working conditions may require.

The intermediate walls 16 have openings 32 therethrough, and the foremost ones of such openings permit of the passage and vertical adjustment of the cross shaft 27.

Vertical aprons, one of which is indicated at 33, are mounted onand project rearwardly from-the front wall 14, whereby to lap the end walls 13 and the intermediate walls 16 in any position of adjustment of said front wall. 14.

The end to end, transversely extending, forwardly facing baffie plates 18-being spaced ahead of the rear wall 12, including lip 5form an open bottom, upwardly extending, surge damping chamber 34 which extends the full width of the hopper 10, even though intersected by the intermediate walls 16.

When the slab laying machine is in operation and advancing along the sub-grade 3, concrete mix is supplied to the aforementioned mix-receiving portion or area of hopper 10 as the bucket 8 is shuttled back and forth transversely of the direction of travel; such mix, indicated at 35, thence being continuously and directly distributed on the sub-grade from such portion of said hopper. The rate of distribution of the mix from the hopper is such that a head 36 of the mix normally remains in said hopper, but which head does not rise above the upper edges of the baffle plates 18. For the purpose of clarity, a portion of the mix 35 is shown as broken away below the head 36, as in FIG. 1.

As the hopper always contains a residual supply of mix, the latter acts to level off irregularities or variance in the flow of said mix from the mixer or the like to the bucket 8.

With the mix continuously and directly distributing from the hopper 10 onto the sub-grade 3, being vibrated and consolidated by the vibrators 23 and 25, such mix is then spread by the pan 4 to form the slab, indicated at 37.

The vibrators 25 are so located relative to the mix receiving and accumulating portion of the hopper to cause an initial consolidation of the mix as first delivered to the sub-grade beneath said hopper. The vibrator 23, whose low point is substantially flush with the pan, further consolidates the mix, driving the heavier rock downward, and bringing grout to the surface as desirable for proper fin- 18 mg.

Due to the fact that the head 36 of the mix in the hopper 10 is variable for the reason previously described, the head pressure of said mix as distributed onto thesubgrade. 3 increases or decreases and heretofore caused the undesirable surging in the mix beneath the pan 4 and waves in the resultant slab. Further-aud although normally effective to aid in countering such surging-the vibrators 23 and 25 may, under certain circumstances, have a contrary effect as, for example, upon stopping of the machine without stopping the vibrators, starting the vibrators 'before starting the machine, or variation of travel speed inconsistent with the amount of vibration.

With the present hopper unit, a quantity of the mix, as distributed on the sub-grade 3 from the hopper 10, willahead of pan 4rise or fall in the surge damping chamber 34, as a relief area or the point of least resistance, as at 38, upon increase or decrease, respectively, in the head pressure of the mix. With such rise and fall of the mix in the surge damping chamber 34, the mix beneath the pan 4 is subject only to a substantially constant head pressure so that the pan produces a slab having a smooth uniform surface. Such substantially constant head pressure beneath the pan is attained by virtue of the fact that variance in head pressure ahead of the pan is equalized through the medium of the surge damping chamber 34 functioning as described. In addition to equalizing surging caused by differential head pressure, the chamber 34 is also functional to damp surging resultant from other factors.

Further, the surge damping chamber 34 provides a minimum head for the effective discharge or release of entrapped air from the mix as it is consolidated and immediately before entry beneath and working by the pan.

Under certain circumstances, the slab laying machine may be reversed in its direction of travel; i.e. run rear- Ward'ly for a short distance before again advancing. When the machine is so run rearwardly, the transverse bafile plates 18 are free to swing forwardly and upwardly, and hence do not constitute a drag on any portion of the mix that may extend upwardly into the surge damping chamber 34.

From the foregoing description, it will be readily seen that there has been produced such a device as substantially fulfills the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be restored to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful and upon which Letters Patent is desired:

1. In a slab laying machine which includes a forwardly movable above-ground slab forming pan, and a mix-receiving hopper disposed immediately ahead of the pan and open to the ground, the hopper including a rear wall extending upwardly from the front end of the pan and transversely of the machine, and forwardly extending end walls; a transversely extending upstanding baffle plate structure in the hopper extending between the end walls ahead of and relatively close to but spaced from the rear wall, means to feed mix into the hopper ahead of the bafile plate structure and to a level above the lower edge thereof, such structure being disposed with said lower edge a material distance above the pan; the lower portion of the rear wall being disposed with a downward slope to the rear; and a transverse tubular vibrator extending between the end walls and located in a transverse plane between said wall portion and the lower edge of the bafile plate structure and in a horizontal plane adjacent but slightly above the level of the pan but below that of said lower edge of the baffle plate structure.

2. In a slab laying machine which includes a forwardly movable above-ground slab forming pan, and a mix-receiving hopper disposed immediately ahead of the pan and open to the ground, the hopper including a rear wall extending upwardly from the front end of the pan and transversely of the machine, and forwardly extending end walls; a transversely extending upstanding bafile plate structure in the hopper extending between the end walls ahead of and relatively close to but spaced from the rear wall, means to feed mix into the hopper instead of the baffle plate structure and to a level above the lower edge thereof, such structure being disposed with said lower edge a material distance above the pan, and means pivotally mounting the baffle plate structure at its upper edge in the hopper for forward swinging movement from a predetermined normal position.

3. In a slab laying machine which includes a forwardly movable above-ground slab forming pan, and a mix-receiving hopper disposed immediately ahead of the pan and open to the ground, the hopper including a rear wall extending upwardly from the front end of the pan and transversely of the machine, and forwardly extending end walls; a transversely extending upstanding baffle plate structure in the hopper extending between the end walls ahead of and relatively close to but spaced from the rear wall, means to feed mix into the hopper ahead of the baffle plate structure and to a level above the lower edge thereof, such structure being disposed with said lower edge a material distance above the pan; the baflle plate structure comprising a plurality of separate normally alined baffle plates, with separate means separately pivoting the bafile plates at their upper edges in the hopper for fore and aft swinging movement, and stop means in the hopper preventing rearward swinging of the baffle plates from a predetermined position.

4. A machine, las in claim 3, in which said pivot means comprises end trunnions on each bafile plate and brackets mounted on the hopper, each bracket having a vertical row of notches to selectively and turnably seat the trunmons.

5. In a slab laying machine which includes a forwardly movable above-ground slab forming pan, and a mix-receiving hopper disposed immediately ahead of the pan and open to the ground, the hopper including a rear wall extending upwardly from the front end of the pan and transversely of the machine, end walls, and a front wall; a longitudinally extending vibrator disposed in the hopper relatively close to the ground, and means mounting said vibrator in connection with the front wall for vertical adjustment relative thereto; said means comprising an arm projecting rearwardly from and pivoted at its front end on the front wall, means connected to the arm adjacent its rear end to swing said arm about its pivot and to hold the arm in any position of adjustment, and a spring mount connecting the arm adjacent its rear end and the vibrator adjacent its forward end.

References Cited in the file of this patent UNITED STATES PATENTS 1,250,809 Davis Dec. 18, 1917 2,072,479 Hadley Mar. 2, 1937 2,101,031 Little Dec. 7, 1937 2,138,103 Jorgensen Nov. 29, 1938 2,225,015 Le Belle Dec. 17, 1940 2,332,687 Bailey Oct. 26, 1943 2,332,688 Bailey Oct. 26, 1943 2,393,954 Baker Feb. 5, 1946 2,479,800 Williams Aug. 23, 194-9 2,598,903 Gebhard June 3, 1952 2,623,446 Clark et a1. Dec. 30, 1952 2,663,231 Wood Dec. 22, 1953 2,669,915 McOonnaughay Feb. 23, 1954 2,842,036 Overman July 8, 1958 2,876,013 Neflf Mar. 3, 1959 2,899,877 Phillips et al Aug. 18, 1959 3,035,499 Domenighetti May 22, 1962 

2. IN A SLAB LAYING MACHINE WHICH INCLUDES A FORWARDLY MOVABLE ABOVE-GROUND SLAB FORMING PAN, AND MIX-RECEIVING HOPPER DISPOSED IMMEDIATELY AHEAD OF THE PAN AND OPEN TO THE GROUND, THE HOPPER INCLUDING A REAR WALL EXTENDING UPWARDLY FROM THE FRONT END OF THE PAN AND TRANSVERSELY OF THE MACHINE, AND FORWARDLY EXTENDING END WALLS; A TRANSVERSELY EXTENDING UPSTANDING BAFFLE PLATE STRUCTURE IN THE HOPPER EXTENDING BETWEEN THE END WALLS AHEAD OF AND RELATIVELY CLOSE TO BUT SPACED FROM THE REAR WALL, MEANS TO FEED MIX INTO THE HOPPER INSTEAD OF THE BAFFLE PLATE STRUCTURE AND TO A LEVEL ABOVE THE LOWER EDGE THEREOF, SUCH STRUCTURE BEING DISPOSED WITH SAID LOWER EDGE A MATERIAL DISTANCE ABOVE THE PAN, AND MEANS PIVOTALLY MOUNTED THE BAFFLE PLATE STRUCTURE AT ITS UPPER EDGE 